Feeding Bees with Sugar Syrup

Our hives didnt make much honey because of rainy and cold summer. Its or feed with sugar or let them starve. Even though sugar is not good for bees it is better than nothing. I feel bees are to be wintered on their own honey always ... Except in a case when the nectar flow failed because of bad weather. I made a simple syrup feeder for each top bar hive. Each jar holds 500g of sugar desolved in 6dl of boiled water (sugar 5:3 water).
I will feed approx 15kg of sugar per hive. Let see how long will it take for the bees to empty those sugar syrup jars.

jar holder is made in such a way so bees can come under the jar and eat the syrup through small holes drilled in the lock.

the jars are filled with the premixed syrup and the feeder is assembled before turning it upside down into the feeding position. Some syrup will drip out when doing this but will soon stop dripping

small wholes in the lid for the bees to feed on sugar syrup